1. Field of the Invention
The present invention relates to a liquid crystal display, and more particularly to a liquid crystal display driven according to a dot inversion method using a data driver driven according to a column inversion method, wherein all liquid crystal cells of a liquid crystal display panel express images at a uniform brightness.
2. Description of the Related Art
Generally, liquid crystal displays typically include a liquid crystal display panel having a plurality of liquid crystal cells arranged in a matrix pattern and driving circuit for driving the liquid crystal display panel. To display pictures, liquid crystal displays control light transmittance characteristics of the liquid crystal cells in accordance with inputted video signals.
The liquid crystal cells are located at areas defined by crossings of gate lines and data lines. Each the liquid crystal cell is provided with a common electrode and a pixel electrode with which an electric field may be generated. Each pixel electrode is connected to a corresponding data line via a switching device such as a thin film transistor (TFT). A terminal of a TFT is connected to a gate line such that video signals may be applied to corresponding pixel electrodes. The driving circuit includes a gate driver for driving gate lines, a data driver for driving data lines, and a common voltage generator for driving the common electrode.
The gate driver sequentially scans the gate lines of the liquid crystal display panel, supplies gate signals to gate lines, and drives the liquid crystal cells on the liquid crystal display panel one gate line at a time. Whenever a gate signal is supplied to a gate line, the data driver supplies suitable video signals to each of data lines crossing that scanned gate line while the common voltage generator supplies common voltage signals to the common electrode. Depending on the video signal applied to the data line, an orientation of molecules of liquid crystal material provided within the liquid crystal cell, between the pixel and common electrodes, may be altered and the light transmittance of the liquid crystal cell may be controlled. Accordingly, as the light transmittances of each of the liquid crystal cells in the liquid crystal display panel are individually controlled, the liquid crystal display panel may display a picture.
FIG. 1 illustrates a schematic view of a related art liquid crystal display.
Referring to FIG. 1, liquid crystal displays typically include a liquid crystal display panel 2 having a plurality of liquid crystal cells arranged in a matrix pattern, a gate driver 4 for driving gate lines GL1 to GLn arranged in the liquid crystal display panel 2, and a data driver 6 for driving data lines DL1 to DLm also arranged in the liquid crystal display panel 2.
Each of the liquid crystal cells include a TFT that responds to gate signals applied to the gate lines GL1 to GLn by supplying video signals, applied to the data lines DL1 to DLm, to the liquid crystal cells. Each liquid crystal cell can be represented as a pixel electrode and a common electrode connected to each other via a TFT and a liquid crystal capacitor Clc. A storage capacitor (not shown), for maintaining a voltage of the video signal, is included within the liquid crystal cell. The storage capacitor maintains the charge within liquid crystal capacitor Clc until the next video signal is supplied.
Storage capacitors of liquid crystal cells are formed between preceding gate electrodes and pixel electrodes of each liquid crystal cell. The gate driver 4 sequentially applies gate signals to gate lines GL1 to GLn to drive the corresponding TFTs. The data driver 6 converts inputted video data into analog video signals and supplies analog video signals, specific to the scanned gate line, to the data lines DL1 to DLm during the period when the gate signal is supplied to the scanned gate line. Additionally, the data driver 6 converts inputted video data into analog video signals using gamma voltages supplied from a gamma voltage generator (not shown).
Liquid crystal cells within liquid crystal display panels such as those illustrated in FIG. 1 may be driven according to various inversion methods including frame, line, column, and dot inversion methods.
When driven according to the frame inversion method, the polarity of video signals supplied to the liquid crystal cells is inverted every frame.
Referring to FIGS. 2A and 2B, when driven according to the line inversion method, the polarity of video signals supplied to liquid crystal cells connected to a gate line is opposite the polarity of video signals supplied to liquid crystal cells connected to gate lines adjacent that gate line. Further, the polarities of the video signals applied to the liquid crystal cells are inverted every frame. Driving liquid crystal cells by the line inversion method, however, is disadvantageous in that a flicker phenomenon is induced in horizontal lines due to electrical cross-talk between liquid crystal cells arranged along the gate lines.
Referring to FIGS. 3A and 3B, when driven according to the column inversion method, the polarity of video signals supplied to liquid crystal cells connected to a data line is opposite the polarity of video signals supplied to liquid crystal cells connected to data lines adjacent that data line. Further, the polarities of the video signals applied to the liquid crystal cells are inverted every frame. Driving liquid crystal cells by the column inversion method, however, is disadvantageous in that a flicker phenomenon is induced in vertical lines due to electrical cross-talk between liquid crystal cells arranged along the data lines.
Referring to FIGS. 4A and 4B, when driven according to the dot inversion method, the polarity of a video signal supplied to a liquid crystal cell is opposite the polarity of video signals supplied to adjacent liquid crystal cells (e.g., liquid crystal cells connected to adjacent gate and data lines). Further, the polarities of the video signals applied to the liquid crystal cells are inverted every frame. Driving liquid crystal cells by the dot inversion method offsets any flicker phenomenon that may be induced between vertically or horizontally adjacent liquid crystal cells. Accordingly, pictures generated by the liquid crystal display panel driven using the dot inversion method have superior qualities over pictures generated by liquid crystal display panels driven using other inversion methods.
Use of the dot inversion method, however, is disadvantageous in that the polarity of video signals supplied from the data driver to the data line need to be inverted in horizontal and vertical directions and individual pixel voltages required by the dot inversion method are typically greater than those required by other inversion methods. Accordingly, liquid crystal displays driven using a dot inversion method typically consume a relatively large amount of power during their operation.
Accordingly, the present invention is directed to liquid crystal display that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An advantage of the present invention provides a liquid crystal display driven by a dot inversion method using a data driver driven by a column inversion method, wherein such a liquid crystal display is capable of consuming a relatively small amount of power during its operation.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. These and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, a liquid crystal display including a liquid crystal display panel having liquid crystal cells at crossings of gate and data lines may include liquid crystal cells consecutively arranged within a column alternately connected to data lines adjacent to left and right sides of the liquid crystal cells and a plurality of dummy liquid crystal cells arranged in first and last ones of successive columns of liquid crystal cells.
In one aspect of the present invention, dummy liquid crystal cells may be formed adjacently on the left of the first data line and adjacently on the right of the last data line.
In another aspect of the present invention, among the dummy liquid crystal cells included in the first column, the dummy liquid crystal cells arranged in even numbered horizontal lines may be connected to the first data line, and among the dummy liquid crystal cells included in the last column, the dummy liquid crystal cells arranged in odd numbered horizontal lines may be connected to the last data line.
In yet another aspect of the present invention, among the dummy liquid crystal cells included in the first column, the dummy liquid crystal cells arranged in odd numbered horizontal lines may be connected to the first data line, and among the dummy liquid crystal cells included in the last column, the dummy liquid crystal cells arranged in even numbered horizontal lines may be connected to the last data line.
In still another aspect of the present invention, the dummy liquid crystal cells may be formed to overlap with a black matrix.
According to the principles of another aspect of the present invention, a liquid crystal display panel may include a plurality of dummy liquid crystal cells arranged within first and second columns a liquid crystal cells, a first dummy data line arranged adjacently to the left of the dummy liquid crystal cells to be connected with dummy liquid crystal cells formed within the first column, and a second dummy data line arranged adjacently to the right of the dummy liquid crystal cells to be connected with dummy liquid crystal cells formed within the second column.
In one aspect of the present invention, among the dummy liquid crystal cells within the first column, the dummy liquid crystal cells arranged in odd numbered horizontal lines may be connected to the first dummy data line, and among the dummy liquid crystal cells within the last column the dummy liquid crystal cells arranged in even numbered horizontal lines may be connected to the second dummy data line.
In another aspect of the present invention, among the dummy liquid crystal cells within the first vertical line, the dummy liquid crystal cells arranged in even numbered horizontal lines may be connected to the first dummy data line, and among the dummy liquid crystal cells within the last vertical line the dummy liquid crystal cells arranged in odd numbered horizontal lines may be connected to the second dummy data line.
In yet another aspect of the present invention, the dummy liquid crystal cells may be formed to overlap with a black matrix.
According to the principles of an aspect of the present invention, a liquid crystal display may include a first resistor group coupled to the first of successive data lines, and a second resistor group coupled to the last of successive data lines.
In one aspect of the present invention, a resistance value of first resistors included within the first resistor group and a resistance value of second resistors included within the second resistor group may be substantially equal to the resistance value of a liquid crystal cell.
In another aspect of the present invention, a number of first resistors included within the first resistor group may be substantially half of the number of liquid crystal cells arranged within a column.
In yet another aspect of the present invention, a number of second resistors included within the second resistor group may be substantially half of the number of liquid crystal cells arranged within a column.
In still another aspect of the present invention, the first of successive data lines may be connected to liquid crystal cells arranged in odd numbered horizontal lines and the first resistors may be arranged in every even numbered horizontal line.
In a further aspect of the present invention, the last of successive data lines may be connected to the liquid crystal cells arranged in even numbered horizontal lines and the second resistors may be arranged in every odd numbered horizontal line.
In still a further aspect of the present invention, the first of successive data lines may be connected to liquid crystal cells arranged in even numbered horizontal lines and the first resistors may be arranged in every odd numbered horizontal line.
In yet a further aspect of the present invention, the last of successive data lines may be connected to liquid crystal cells arranged in odd numbered horizontal lines and the second resistors may be arranged in every even numbered horizontal line.
In an additional aspect of the present invention, the first and the second resistors may be formed by providing the first and last of successive data lines with an increased width.
In another aspect of the present invention, the first and the second resistors may be formed by providing the first and last of successive data lines with an increased thickness.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.